Jeffrey T. Gray

Learn More
OBJECTIVE To test feed and feed ingredients on swine farms for Salmonella organisms and to analyze data from these farms to determine risk factors associated with Salmonella organisms in the feed and feed ingredients. DESIGN Epidemiologic survey and retrospective case-control study. SAMPLE POPULATION 30 swine farms. PROCEDURE Samples of feed and feed(More)
The objective of this study was to determine the long-term effects of feeding monensin on methane (CH4) production in lactating dairy cows. Twenty-four lactating Holstein dairy cows (1.46 +/- 0.17 parity; 620 +/- 5.9 kg of live weight; 92.5 +/- 2.62 d in milk) housed in a tie-stall facility were used in the study. The study was conducted as paired(More)
This study was designed to describe the percentage of cattle shedding Escherichia coli O157:H7 in Midwestern U.S. feedlots and to discover relationships between the point prevalence of cattle shedding the organism and the characteristics of those cattle or the conditions of their pens. Cattle from 29 pens of five Midwestern feedlots were each sampled once(More)
Transmission of Salmonella typhimurium in swine is traditionally believed to occur by the fecal-oral route, with invasion through the intestinal wall and Peyer's patches. However, involvement of the upper respiratory tract may be equally important. An esophagotomy was performed on 6- to 8-week-old pigs. Esophagotomized pigs were challenged intranasally with(More)
The conduct of randomized controlled trials in livestock with production, health, and food-safety outcomes presents unique challenges that may not be adequately reported in trial reports. The objective of this project was to modify the CONSORT (Consolidated Standards of Reporting Trials) statement to reflect the unique aspects of reporting these livestock(More)
A national study of health and management of cattle in feedlots was conducted. Within this study, the prevalence of Salmonella spp. in fecal samples was determined. Fifty fecal samples were collected from each of 100 feedlots. Within each feedlot, 25 fresh fecal samples were collected from the floor of the pens of cattle which had been on feed the shortest(More)
This experiment was designed to study the natural transmission of Salmonella choleraesuis in swine. Forty pigs were divided into three groups. Group 1 (n = 12) was challenged with 10(8) CFU of S. choleraesuis per ml by intranasal inoculation. One day postinoculation (p.i.), group 2 (n = 24) was commingled with group 1. Group 3 (n = 4) served as uninoculated(More)
Escherichia coli O157:H7 was recovered from colon fecal samples of pigs. Polymerase chain reaction confirmed two genotypes: isolates harboring the eaeA, stx(1), and stx(2) genes and isolates harboring the eaeA, stx(1), and hly(933) genes. We demonstrate that swine in the United States can harbor potentially pathogenic E. coli O157:H7.
In an extensive, multiyear study of antibiotic resistance from wastewater oxidation ponds, five mobile home park wastewater oxidation ponds in Clarke and Oconee counties were shown to be discharging high numbers of antibiotic-resistant bacteria into the waterways of North Georgia. This effluent contributed to higher nitrogen, phosphorus, and fecal coliform(More)
A total of 112 out of 5,709 Salmonella enterica isolates from domestic animal species exhibited decreased susceptibilities to ceftiofur and ceftriaxone, and each possessed the blaCMY gene. Ten Salmonella serotypes were significantly more likely to include resistant isolates. Isolates from turkeys, horses, cats, and dogs were significantly more likely to(More)